This study is designed to investigate patterns of hemodynamic responses of prefrontal cortex during tasks of executive function (EF) in a mild traumatic brain injury (mTBI) group. The hemodynamic cortical responses will be measured with an innovative functional imaging technique, functional near infrared spectroscopy (fNIRS). Using a fNIRS system provides the opportunity of examing on-task brain functioning without many of the limitations inherent in MR-based research (e.g., subject confinement, limitation in paradigm development). Standard measures of EF will be administered to the participants while being scanned with the in-house fNIRS system. The hemodynamic responses will be compared between the mTBI and control groups. The level of cognitive performance will be compared to the hemodynamic response both within groups and between groups. It is expected that the mTBI group will show increased hemodynamic responses when compared to the control group. It is also expected that the level of prefrontal activation will be associated with the level of cognitive performance. These results are expected to provide empirical evidence that changes occur in the prefrontal cortex in individuals with mTBI. These results will demonstrate that NIRS is a useful instrument for predicting cognitive outcome and provide diagnostic information when recommending individuals for cognitive rehabilitation. [unreadable] [unreadable] [unreadable]